The description of not quite correct. You'll need a 16mm spanner and/or a 14mm hex key. As 16mm is not a standard metric size you'll be on adjustables. It's not the finest quality tool, what do you expect for the price, and if I was needing it regularly I'd get something better. But I'm not, and it did the job so I'm happy.
4x Right Angle Gold 4mm Banana Plug Audio Speaker Cable Connector Screw Type -UK